As a method for industrially producing dihydroxybenzene typified by resorcin, there is known a method in which benzene and propylene are reacted to obtain diisopropylbenzene, the diisopropylbenzene is oxidized to give diisopropylbenzene hydroperoxide, and the diisopropylbenzene hydroperoxide is acid-decomposed to give dihydroxybenzene and acetone (see, e.g., patent document 1).
Here, dihydroxybenzene obtained by the above-described method is crude dihydroxybenzene containing isopropenylphenol, hydroxyacetophenone and the like as impurities. Thus, it is necessary to perform purification by removing the above-described impurities and the like from the crude dihydroxybenzene, for obtaining dihydroxybenzene as a product.
It is also known that dihydroxybenzene is required to have high level product purity depending on applications and a purification method for obtaining highly purified dihydroxybenzene has been developed (see, e.g., patent document 2).
As a method for purifying crude dihydroxybenzene, methods of adding water and an extraction solvent to crude dihydroxybenzene and extracting dihydroxybenzene into an aqueous phase are described in patent document 3 and patent document 4.
However, there is a desire for methods of efficiently obtaining dihydroxybenzene which is more highly purified than in conventional methods.    (Patent document 1) JP-A No. 53-23939    (Patent document 2) JP-B No. 61-18537    (Patent document 3) JP-A No. 64-38    (Patent document 4) JP-A No. 2002-363118